Previously, I just called and asked to speak to a manager or I would get the name and fax number of who I was supposed to contact - then I would fax my participation letter (from the office) and a letter stating my request and contact information.
If I called and was able to talk to someone, then I would tell them what I would like to do (tag day) in support of WEBC benefiting the PMH.
It looks like every club has their own rules and regulations but from my experience, they don't have designated days for tag days.
Just call and ask - you'll get the rest of the information from the manager.

(Ask for a whole weekend ... usually they will let you come Saturday and Sunday).

Good Luck.